Supplemental Materials and Methods from TMPRSS2–ERG-Mediated Feed-Forward Regulation of Wild-Type ERG in Human Prostate Cancers
ARTICLE ABSTRACT
Recurrent gene fusions involving ETS family genes are a distinguishing feature of human prostate cancers, with TMPRSS2–ERG fusions representing the most common subtype. The TMPRSS2–ERG fusion transcript and its splice variants are well characterized in prostate cancers; however, not much is known about the levels and regulation of wild-type ERG. By employing an integrative approach, we show that the TMPRSS2–ERG gene fusion product binds to the ERG locus and drives the overexpression of wild-type ERG in prostate cancers. Knockdown of TMPRSS2–ERG in VCaP cells resulted in the downregulation of wild-type ERG transcription, whereas stable overexpression of TMPRSS2–ERG in the gene fusion-negative PC3 cells was associated with the upregulation of wild-type ERG transcript. Further, androgen signaling-mediated upregulation of TMPRSS2–ERG resulted in the concomitant upregulation of wild-type ERG transcription in VCaP cells. The loss of wild-type ERG expression was associated with a decrease in the invasive potential of VCaP cells. Importantly, 38% of clinically localized prostate cancers and 27% of metastatic prostate cancers harboring the TMPRSS2–ERG gene fusions exhibited overexpression of wild-type ERG. Taken together, these results provide novel insights into the regulation of ERG in human prostate cancers. Cancer Res; 71(16); 5387–92. ©2011 AACR.
